Northern Prairie Wildlife Research Center
SENSITIVE FERN FAMILY (Onocleaceae)
IND. STATUS: FACW
FIELD CHARACTERISTICS: A clonal, perennial fern with erect, coarse, stout leafy crowns growing to a height of 0.5-2(3)m. The fronds are of two types, The sterile fronds are green and pinnate-pinnatifid with a fine pubescence along the rachis, particularly in the spring. The alternate pinnae are gradually reduced toward the base of the frond. The fertile frond is shorter than the sterile frond, brown at maturity, and has inrolled pinnae which enclose the sporangia. The fertile fronds are produced between midsummer and early fall and persist through the winter. The black rhizomes are large and stoloniferous.
ECOLOGICAL NOTES: Ostrich fern is a circumboreal species of swamps, floodplain hardwoods, and shady moist woods and thickets. It is often found growing on alluvial deposits. This species typically occurs north of the tension zone.
SOURCE: Gleason and Cronquist (1991) and Tryon (1980).